With the miniaturization and sophistication of semiconductor devices, various processes for densely packaging the components have been under development. The FCB may be employed as one of the methods for realizing the dense packaging. During the FCB process of a semiconductor chip, an inner connecting terminal formed of a solder bump is formed on the electrode of the semiconductor chip, and is packaged on a mounted portion, such as an interconnection substrate or another semiconductor chip. The solder bump is thermally processed into a molten state to form a solder ball. It is spread on the electrode surface on the mounted portion and solidified to become the solder bump again. The electrode on the semiconductor chip and the electrode on the mounted portion are thus physically and electrically coupled with each other via the solder bump.
In order to suppress the risk of producing a defective semiconductor device, an inspection to confirm whether the electrode and the solder bump are appropriately bonded needs to be conducted promptly. As the bonded portion between the electrode and the solder bump is hidden behind the semiconductor chip with the flip-chip structure, a mere visual inspection may not be enough to confirm the workmanship of the bonded portion. That may be the reason why an X-ray image pick-up or an electrical continuity test is performed on the subject area.
During the X-ray image pick-up, the determination with respect to the acceptability of the bonded state is made based on the relative positional relationship between the solder bump and the electrode on the mounted portion picked up by the X-ray. In the case where the electrode on the mounted portion is considerably thin, only the image of the solder bump without the image of the electrode is picked up by the X-ray. In this case, it may be difficult to confirm the bonded state from the X-ray image picked up from the top. So the image pick-up is required to be performed diagonally or laterally using a high magnification X-ray device. The aforementioned inspection process requires not only an expensive X-ray device but also relatively long inspection time. Furthermore, the prolonged inspection process may make it difficult or useless to perform an inspection for confirming the electric continuity of the bonded portion.